This invention relates generally to rail electrification systems, and more particularly to hanger devices for suspending conductor rails in operative relation, forming a track for engagement by conductor shoes.
In the past, numerous rail hanger devices have been proposed and produced. A number of these consisted of a transverse cross bar from which there were suspended multiple clamps each having flange portions which engaged opposite sides of the conductor rail being supported. The latter typically had elongate, V-shaped grooves in its opposite sides, into which the similarly shaped portions of the flanges were seated. After insertion of the conductor rail into the clamp, the flanges were drawn together, as by tightening a bolt extending through both pieces.
While this arrangement operated satisfactorily, it had several disadvantages. Such conductor rail assemblages were usually suspended overhead from beams and were frequently not readily accessible to the worker without the use of a ladder or other platform. Accordingly, it was often found to be awkward or difficult to loosen and tighten the screws associated with such clamps. Operations of this type often required the use of both hands while balancing oneself on a ladder, this resulting in increased installation time and presenting a hazard to the worker. In addition, the worker had to judge how much to pull up on the screws, which had to be sufficiently tight to insure that the rails would not become loose or drop down. At the same time it was found to be desirable to not clamp the rails too tightly, whereby they could slide longitudinally in the clamps, with the normal expansion and contraction due to temperature. Excessive tightening of the clamps caused the rails to bow when they expanded, thus disrupting the proper operation and tracking of the collector shoes.